LTR Analyzer released

[nd5y]

the bursts don't contain enough data bits anyway (about 10 out of 40!).

The bursts that don't decode are about .17 sec long and the ones that do decode are about .26 sec.
If they aren't transmitting the whole burst, won't all their radios show no service all the time?
I also noticed that only a couple of the systems in my area transmit a CW ID. The rest just send the BUSY/CWID message for about 1 second or so with no audio.

 

[rescueone]

OK, I've got the program running and I'm seeing data like what's been posted. I can figure out the LCN configuration to a certain extent. If you know only 1 freq and lets say it ID's as Home channel 3, but it shows 3 other LCN's, (5,11,18), how do I find the other 3 freq's used by this system? Is there anyway to find a SYS-ID (like Trunker does) so I can look it up in a database (either here or at the FCC) to determine which freq's are in the system?

 

[pro92b]

OK, I've got the program running and I'm seeing data like what's been posted. I can figure out the LCN configuration to a certain extent. If you know only 1 freq and lets say it ID's as Home channel 3, but it shows 3 other LCN's, (5,11,18), how do I find the other 3 freq's used by this system? Is there anyway to find a SYS-ID (like Trunker does) so I can look it up in a database (either here or at the FCC) to determine which freq's are in the system?

LTR has no sysid so the best you can do is check FCC records for the licensee.

 

[pro92b]

Here is a screen shot from 1.2. The first line has a display problem with Area.

The line showing Unknown function should probably display END.

 

[EricCottrell]

The company that runs this system does have a wide area Passport system here so it is likely a Trident controller. This particular system appears to be LTR regular only since the idle bursts are 10 seconds apart and the log shows 6 to 7 regular LTR OSW's per second. That would leave no time for Passport OSW's.

Hello,

From the configurations I have seen the assigned Home Channels are either Passport or Regular LTR and not both. This avoids a situation where the data would be mixed. What you would see on "overflow" repeaters are some transmissions will not decode if the decoder does regular LTR only.

The Regular LTR could be at one of the Passport sites and use the same controller. The statewide Passport system in CT offers two tiers of service, local (Regular LTR) and wide-area (Passport). Harvard University was using Regular LTR with Trident controllers for awhile then reconfigured to Passport only.

73 Eric

 

[DaveNF2G]

Some Multi-Net logs would help.

I'd be happy to send some, but I'm not sure how to get any. I use LTRunker to track the local system, but to my knowledge it doesn't create a log of raw CC data.

I'm not sure that recording the CC would help, either, as it's subaudible.

 

[pro92b]

I'd be happy to send some, but I'm not sure how to get any. I use LTRunker to track the local system, but to my knowledge it doesn't create a log of raw CC data.

I'm not sure that recording the CC would help, either, as it's subaudible.

Use Ltrdump to create log files. I have some archived and can send them to Slicerwizard off-list.

 

[EricCottrell]

I'd be happy to send some, but I'm not sure how to get any. I use LTRunker to track the local system, but to my knowledge it doesn't create a log of raw CC data.

I'm not sure that recording the CC would help, either, as it's subaudible.

Hello,

You need to use LTRDump but then you can not trunktrack with it. You could try splitting the slicer output between two computers and run LTRTrunk on one and LTRDump on the other.

73 Eric

 

[slicerwizard]

1.2 crashes for me the first time it trys to decode anything. 1.1 works great.
Jim

Hopefully, 1.3 behaves.

 

[slicerwizard]

I can even get partial decodes on distant repeaters that are too weak to open the squelch.

I guess I did something right.

 

[slicerwizard]

If they aren't transmitting the whole burst, won't all their radios show no service all the time?

Apparently not. Had a local system here that dropped the first 15 bits of every idle burst, but the radios didn't care. I guess the radio vendors know how bad some systems are set up, so maybe the firmware is happy if it sees a periodic carrier on the home channel.

 

[slicerwizard]

If you know only 1 freq and lets say it ID's as Home channel 3, but it shows 3 other LCN's, (5,11,18), how do I find the other 3 freq's used by this system?

Do an FCC lookup on the frequency you do know. Look for more frequencies:

- with the same callsign

- licensed to the same licensee

- licensed to the same location

 

[slicerwizard]

Here is a screen shot from 1.2. The first line has a display problem with Area.

The line showing Unknown function should probably display END.

Fixed in 1.3

 

[slicerwizard]

I'm not sure that recording the CC would help, either, as it's subaudible.

Recordings of discriminator audio are fine. The datastream is quite audible.

 

[pro92b]

1.3 still shows end of CW ID as Unknown function.

12/23/2007 17:40:01   + OSW: 1 07 07 255 09 25  BUSY/CWID  FREE=9  LCN=7
12/23/2007 17:40:01   + OSW: 1 07 07 255 11 22  BUSY/CWID  FREE=11  LCN=7
12/23/2007 17:40:02   + OSW: 1 31 07 255 07 24  Unknown function  LCN=7
12/23/2007 17:40:12   + OSW: 1 07 07 255 07 36  IDLE  LCN=7

 

[kd5dga]

Just like any program at it first stages there are going to be a few items to iron out. I am thankfull to see a LTR decoding program that does not involve a dataslicer and filter arrangement and runs strictly from the soundcard.
Now if I can only get my act together on running from the command line to get a log.

 

[DaveNF2G]

Excuse me for having to ask this, but my brain has been a bit fuzzy from a cold. Can LTR Analyzer be used to generate a MultiNet logfile even if it doesn't "understand" the datastream?

 

[EricCottrell]

1.3 still shows end of CW ID as Unknown function.

12/23/2007 17:40:01   + OSW: 1 07 07 255 09 25  BUSY/CWID  FREE=9  LCN=7
12/23/2007 17:40:01   + OSW: 1 07 07 255 11 22  BUSY/CWID  FREE=11  LCN=7
12/23/2007 17:40:02   + OSW: 1 31 07 255 07 24  Unknown function  LCN=7
12/23/2007 17:40:12   + OSW: 1 07 07 255 07 36  IDLE  LCN=7

Hello,

That unknown function is the Unit Unkey, in this case the CW ID stopping. It is a common enhanced LTR function supported by a lot of controllers.

73 Eric

 

[slicerwizard]

1.3 still shows end of CW ID as Unknown function.

Oops. Fixed.

 

[slicerwizard]

Excuse me for having to ask this, but my brain has been a bit fuzzy from a cold. Can LTR Analyzer be used to generate a MultiNet logfile even if it doesn't "understand" the datastream?

That's what I thought users would do. Unless there's something about the datastream I'm not aware of.